Method and apparatus for treating gases



July 24, 1934. c, J. WARNKE METHOD AND APPARATUS FOR TREATING GASES Filed April 29, 1933 w NN. m m I|| w u :L I l||I|||| 1 |1|||-L O T MW NN NN @v Patented July 24, 1934 FEE METHD AND APPARATUS FOR TREATINGr GASES cari i. warnte, Elkhart,

Ind., assignor, by'directV and mesne assignments, to The Adams & Westlaire Company, Illinois Chicago, lill., a corporation of Application apra 29, 1933, serial No. ,66891.95l

e claims. (ci., 232o4) C. to 160 C., the relation between the volume of Stated broadly, the purpose oi this invention is` to provide an improved method and apparatus for purifying such gases as hydrogen, helium, neon, argon, krypton, xenon, and the like. It has been found that the so-called chemically pure commerical supplies or" these gases contain small quantities of carbon-dioxide, water vapor, nitrogen, oxygen, hydrocarbons and other impurities which are highly undesirable. When purified by` the method and apparatus of this invention, they are rendered substantially free oftheseimpuri ties. In my copending application, Ser. No. 533,229, led April 27, 1931, I have claimed the particular method and apparatus that is used for purifying hydrogen.

It is also anobject of this invention to prepare certain gases which I have found v to be particularly useful in mercury switches. These gases are more highly resistant to ionization than the gases now used, and are also substantially incapable of reacting with or being absorbed by such metals as platinum, tungsten, molybdenum, tantalum, and vanadium. Mercury switches employing these gases as gas fills are found to have amazingly long life, and vastly improved operating characteristics, and I have claimed the novel combination in a companion application, Ser. No.V 668,496, led April 29, 1933. Y n

A still further object of the invention is to produce the hydrides oi such elements as helium, neon, argon, silicon, and boron in stable form,vat least in their'own atmosphere, and of these I am particularly concerned withvheliurm hydride. These hydrides appear to have certain properties that distinguish them from other gases and make themyery useful.

The earlier textbooks will show lthat helium is commonly regarded as Va typically inert gas, incapable of forming compounds. Numerous attempts have been made to combine helium with other elements, but for the most part, these attempts have met with failure. However, the investigations of certain scientists have tended to disprove that helium is completely inert and there is evidence that under particular circumstances helium can be made to combine with other elements to form compounds.

In Chemical Abstracts, vol. 23 (1929) p; 1537, there is a rsum of certain work performed by Horacio Damianovich with reference to the action of helium on platinum, and briefly it is related thatby means of an electric discharge in a small tube, platinum was deposited in an atmosphere of spectroscopically pure helium. Upon examination of the deposit, it was foundy that absorption of the helium, amounting to from 14 to 34 cc. per gram of the platinum deposited, began with the appearance of the platinumde-v posit. When a deposit was finally decomposed in a vacuum at temperatures ranging from 90 helium evolved the temperature resembled the decomposition relations of heterogeneous sys- Ultra-violet photomicrography` indicated structural diiierences between the vplatinumhelium deposit .and the platinum obtained after thermal decomposition. It was, therefore, proposed-that the helium is held in some state` of combination with a part of the platinum.

Again referring to the foregoing volume of the Chemical Abstracts, there is another reference to the work of the same party on pape 3382. There, it is stated that Damianovich made quantitative experiments illustratingthe absorption or chemical combination of helium with platinum. One arrangement of his Vapparatus consisted of a dis-,- charge tube 2o centimeters long with two very pure platinum electrodes. Receiver-tubes were inserted near the electrodes to catch the platinumfhelium compound of brownish tinge. The other tube was built of quartz and had demountable electrodes. Y

, In vvolume 20v of Chemical Abstracts,` page 560, there is a reference to mercury helide. It is stated that the correct analysis of this compound showed 21.079 parts by weight of mercury combined with 4.18 parts by weight of helium, giv-` ing the simplest formula as HgI-Ieio. On page 2127 ofthe same volume, thereis an airmation of the analysis just given.

In the Chemical Dictionary by Hackhpublished by C. Blackistons Son & Co., Inc., Philadelphia, Pa., it is stated under the heading of helium that, while this substance has a valency of zero and hence forms no ordinary compounds, `excited helium molecules however seem torgive compoundssuch as helides. In the same book, under the heading helides, this substance is dened as being a supposed compound of helium, as mercury helide HgI-Ieio.

In Nature, vol. 144 (1924) at page 861, there is the following statement which relates lto the work of J. J. Manley of Magdalen College, Oxfordzi* i* Under certain conditions and in the presence of an electric glow discharge, mercury and helium combine to form Vmercury helide.- Thhelide is a stable compound, and is not readilyr decomposed except at or above a bright red heat. As the formation of the helide progresses, a vcorresponding decrease in the volume of the helium Y.employed takes place.` On heating the mixed gases (helium and helide) to the required temperature, the original Volume of the helium is restored. The helide is but slightly absorbed by charcoal cooled in liquid air.

In Engineering, vol. 121 (1926), at page 459, there is an Y account of experiments made by' Aston .with gases of the helium group. The experiments showed that under special conditions, the helium group of gases were capable of form-l ico los

:fil

ing temporary compounds presumablyfthe hydrides. By spectrum analysis, Aston found a line in one of his discharge tubes whichcorresponded to an atomic weight of ve and which he concluded to be a hydride of helium. Thesev hydrides, however, were all of temporary character.

Through extensive research, I have devised a method and apparatus for producing a gas which appears to be a stable form .of helium hydride. Its characteristics are not the sameY vas when helium and hydrogen are mixed without any attempt to have them chemically combined, but on the contrary, the new gas exhibits the properties which would be expected of the hydride of helium.

Perhaps the most common way to identify unknown gaseous substances is by spectrum analysis. In order to prove that the gas produced by my method .and apparatus is more than a physical mixture of helium and hydrogen, tests were conducted to show that the gaseous product of my method and apparatus emits a band of light waves thatv is foreign to the spectra of helium, hydrogen and the physical mixture of helium and hydrogen. When chemically pure helium is excited in a Geissler tube, the characteristic spectrum of helium is produced. Likewise when chemically pure hydrogen is excited in a Geissler tube, the characteristic spectrum lines of hydrogen are produced. When the physical mixture 'of helium and hydrogen are analyzed by the spectroscope, the spectrum is the sum of the helium and hydrogen spectra. But when the gaseous product of my method and apparatus is spectroscopically analyzed, an intense and highly persistent line at 5440 angstroms is seen,lwhich line does not occur in the helium or hydrogen spectra or in the spectrum of the physical mixture of helium and hydrogen. rlhis new Vline at 5440 angstroms indicates, without a doubt, that the helium and hydrogen have combined in some way, and there is reason to believe that the new combination has a probable formula Hel-1.

Another test which strongly indicates the formation of helium hydride is known as-the absorption test. Hydrogen is well known to be capable of being absorbed by such metals as platinum, tantaium, columbium and palladium. With tantalum, hydrogen is capable of being absorbed to the lextent 'of four to nine hundred times the volume of the metal. The ability of thesemetals to absorb hydrogen is increased ras the temperature 'of the metal is raised. Thus when 'a quartz tube containing 'tantulum is heated to a temperature of 1G00 C'. and a source of hydrogen isY connected vto the tube, the hydrogen will flow 'into the "quartz tube at an amazing rate. This can be measured by a suitable :iiow meter.

Helium is unlike hydrogen in this respect, and is substantially incapable of bein'g'abs'orbed by hea-ted tantalum. Therefore, if a physical mixture of equal volumes lof helium and hydrogen is passed into the tube containing hot tantalum, the now will be substantially one-half of the iiow which was recorded for hydrogen alone. But when a physical mixture of helium and hydrogen has been irst passed through myapparatus to form helium 'fhydride in accordance with the method disclosed inv this application, and then introduced into the 'quartz tube containing tantalum, we find 'that `'the iow of gas is practically This test, therefore, strongly indicates that the helium and hydrogenhave combined in some manner and are no longer V'free elements.-

While I iirmly believethat helium hydride is formed in a stable state by my method and apparatus, the gaseous product, whatever it is, has many properties which distinguish it from known gases and make it highly useful. The method and apparatus of this invention, therefore, has utility regardless of the chemical composition of the gas that is formed.

Further and other objects and advantages will become apparent as the disclosure proceeds and the description is read inv conjunction with the accompanying drawing, in which Fig. 1 is a side, elevational View of apparatus for practicing my method of treating gases, the parts being broken away to expose the interior of the apparatus;

Fig. 2 is a side, elevational view of the apparatus, a portion of the apparatus being shown in section; and

Fig. 3 is a semi-diagrammatic View showing an optional preliminary step to my process.

For the purpose of this disclosure, it will be assumed that the container 10 is iilled with a physical mixture of helium and hydrogen in the proportion of two volumes of helium for one of hydrogen. If the apparatus is to be used merely for purifying the gas, the container 10 is exchanged for another which'contains the gas to be treated. Reference is made to my copending application, Ser. No. 533,229 filed April 27, 1931 for a speciiic use of the method and apparatus of this invention for purifying hydrogen.

Before physically mixing the helium and hydrogen in the container 10, the two gases may be separately or jointly conducted through a hermetically sealed box 11 into-which liquid air is adapted to be introduced. The source of helium, hydrogen, or helium and hydrogen is indicated diagramrnatically at 12 and the gas is led from the source through a tube 13 and valve 14 to a coil 15 in the box 11. The bottom end of the coil communicates axially with the interior of a cylindrical filter element 16 which is lled with cotton or other filtering material, in order to prevent impurties which are frozen out ofthe gas from passing through the pipe 17 Ainto the container 18. VIn this way, the greater part of the moisture and other impurities which will freeze at the temperature obtainable with liquid air are removed from the gas.

It will be understood that the apparatus shown in Fig. 3 is purely diagrammatic and that any suitable means may be provided for freezing out the grosser quantities of impurities.

My apparatus, as shown in Fig. 1, consists esj;

sentially of a steel block 19 substantially rectangular in form and provided with a plurality of gas chambers 29, 21, 22, 23, 24 and 25, all of which are open at the bottom. The chambers are oonnected in series by inclined passages 26 and preferably the passages 26 are alternately arranged adjacent the top and bottom of the block.

The 'end of the block adjacent to the chamber 20 has an inlet opening 27 for introducing the gas into the apparatus from the container 10. A valve 28 is provided `for regulating the now of gas from the container and it lis Vobvious that the gas when introduced into the apparatus passes successively through chambers 20, 21, 22, 23', 24 and 25 and `finally emerges from the `apparatus through an opening 29.

The bottoms of the chambers are Iclosed by electrode holders `generally designated 130, 31, 32, 33,34 'and 35, each ofV which consists lof a tubular shell-36 which is threaded at 37- into the ibase of the block and is provided with a flange 38 which formsraseat for a gasket 39 so as to.

hermetically seal the interior of the chamber.

The upperends of the shells 36 are internallyV threaded as shown at 40.to .receive the threaded bases of sleeves 41 which extend upwardly a substantial distance along the vertical. axes of the chambers. The sleeves are provided with flanges 42` which. rest upon the tops of the shells 36.

' Each shell is provided witha threaded stem` 43 which is threaded into the base of the shell and is equipped with a cylindrical head 44 the diameter of which is the'same as the internal.

diameter of the shells36. Y

In each of the six chambers inkt-heu*lolockyelec-Vv of one or more metals chosen from a group con-f sisting of sodium, potassium, calcium, black phosphorous, magnesium, caesium, titanium,and

other metals which, because of their ability to decomposeA and/or take up water vapor at elevated temperatures, and their ability to retain it and/ or prevent its reformation at lower temperatures, may be called equivalents. The particular metal or metals that vare used'depend'upon the use to which the'apparatus isput, but in all cases, the material forming one of the Aelectrodesmust be capable of ionizing'to effecta precipitation of impurities from the-gases and perhaps-assist as a catalyst in effecting the desired, result.

The upper refractory electrodes "4 6 arev mounted in specially constructed plugs 47 in which the customary side electrodeis omitted. TheY plugs may b e screwed into suitable openings 48 provided in the top of theblock, or they may be mounted horizontally in the rear wall 49. Therev is some advantage in this latter arrangement, because the plugs are slightly removed from the tops of the chambers Where the temperature is the highest. The lower or vaporizing electrodes 45,-being relatively soft, may be extruded through the sleeve 41 by turning the stems 43in the. shells. `In order that the functioning of the apparatus may at all times be observed, the front wall 50 vof the block` is provided with openings 51'into which steel tubes 52 are threaded carrying a window 53 at their outer endssecured in; place by suitable nuts 54. These windows permit the person us.- ing the apparatus to at all times observe the4 functioning of the apparatus and A adjust thev lower electrodes 45 when necessary.. The potentialfor striking the arc between the electrodes 46 and 45 is supplied from,a. .pow er line 55 having a plurality'of step-up transformers 56 .connectedacross the line. The secondary coils 57 ofthe transformers are connected. to the binding posts of adjacent plugs 47 so asV to form three high potential. circuits in .the block.

'- Thus the electrical circuitV for chambersf20and 21 may be traced from the coil 57' through the plug 47 in the chamber 20, thence through the electrode 45 in the chamber 20, thencefthrough the block 19 to the electrode 45 in thechamber 21; thence to the electrode 46 in the plug of that chamber, and'back to the secondary coil 57.

For best results, the high potential circuits through the electrodes should operate at or about 12,000 volts and 200 milliamperes.

It will be understood that the use of six separate chambersfin theblock 19-isgbut an arbitrary arrangement.` and that a fewer number, or more, may be employe'd.- f

-As' has :beenfpbefore intimated, the material.

used for the electrode v`45 is of primeimportance tothe successful: employment of my method and apparatus. It iis not deiim'telyknownwhether the electrode materialacts as a catalyst or merely becomes more active because of Vbeing ionized underthe 'electric'.arc., The discussion that fol-v lows,. therefore;y is merely explanatory of. what is thought. to occurawhen particular materials are used. Entirely apart from the theoretical explanation remains the fact that when these materials'are used, a new and usefulproduct is formed. v k1 Sodium, potassium,calcium, black phosphorous, magnesium,.csium,. andtitanium are all more or vless hygroscopic incharacter and when vin ionized form under an electric archave the inherent capacity to unite with watervapor to form solids whichv are precipitated from` the *.gas..

Thesemetals also react with carbon dioxide and certain. .other impurities to remove them from thegas.. 1 L

1 It Will be ,understoodV that the term-hygroscopic.as it is used throughout this disclosure: and in the appended claims is intended to signify that the metals are capable of decomposing, uniting with, orotherwisetakingup Water vapor at elevated temperatures, and moreover are capable of tenaciously holding onto the water vapor, and/or preventing. water vapor from forming by a recombination of hydrogen and oxygen when thetemperatures are lowered to normal'. Therefore, any metal having this propertymay be consideredthe equivalent of the named metals unless the prior art forbids thisinterpretation. Sincesodium is one of the mostactive of themetals in they above group, and can be obtainedcommerciallyjin. a'highly purified state, I prefer to use itas the lower .electrode in the first three chambers; i: e. chambers 20, 21 and 22.- The other metals could, of course, be used if desired. Although sodium canbe obtained in a highly purified state, I-'prefer to further purify it by meltingit under vacuum in a container immersed in an oil bath'v ata-temperature of about 350 C. The Vimpuritiesin .the sodium Will rise to the surfaceandwhen -the entire mass-is cooled, the impuritiesmay be cutv from the pure sodium.

Since pure'sodium is relatively soft'at ordinary temperatures, it can be forced through the sleeve 41 with ease by suitable manipulationof the'stem43.- f

The other three vaporizing electrodes may also be sodium, but preferably they contain .some titaniunnor calcium because these metals are better able to combine -with nitrogen impurities and-remove them from the gas. The calcium and titanium also seem to act as catalysts when thei apparatus is being used to form gaseous hydrides, and are, therefore, particularlydesirable when the apparatus is putto this use. Howev'er, itwill' be understood that calcium and titanium merely increase the hydride yieldand do not appear to be iessentialto its formation. As between calcium Vand titanium, the latter appears to be the-better catalyst. The last three vaporizing electrodes are, therefore, preferably composed of a mixture of chemically pure sodium mixed with some titanium. The mixture may be made while the sodium is being purified by placing powdered titanium with the sodium prior to its being melted under vacuum.

r.gen isA passed through the .apparatus and subjectedv toy Athe action of vthe electric 'arcs in; the

presence of ionized hygroseopie metals and par-z ticularly in the presence of titanium, or calcium ;ions, the vgas which issues from theoutlet l29 is characterized by its amazingy dieelectric propy.io

lum. It has anfionizing potential,substaritallyl above hydrogen or helium, and consequently is y'far more eieciive in suppressingfe'lectric: .arcs

i orsome other elementen* to produce a gas having than either of thesev gases alone.r f v y From .the above, it will be understoodk that when ythe apparatusis to be used for puriiieation purposes, thevaporizing electrodes aremadeof anyk of the hygroscopic materials, andpreierably l f sodium. e If vthe gas to be purified contains nitrogen, as an impurity, rsome calciurnnrv titanium should. be used in the yaporizing electrodes. e When theapparatus is lto be usedfor effecting a chemical combinationoi hydrogen with helium e the .particular characteristics that are .desirable rfor use in mercuryswitches, one or more ofA ther vaporizingr electrodes sliotuui contain e calcium vanch/or titanium, .and preferably thelatter in order i0 @brama goodyiadoffihe descargas.k

Itwill be understoodthat so far .as the method I is concerned the necessary hygroscopic andA cata lytic ions may be introduced intov the electric are by some meansother than forming the electrodes vof the desir-ed material.v :For example,r the hygroy s scopic and catalytic'.y materials .be .placed n in .the path of the electriedischarge without makring them a part of :the electrical circuit. l

A slightly diterent apparatus must be `used to form boron and silicon hydride by ythe'methody f .of this invention. Since both boron,V and lsilicon arey solids, they cannot k'be physieallymixed with hydrogen prior to their being introduced into the apparatus. It is, therefore, necessary to ionize the boron and silicon in theapparatus and this can be accomplished either `by using borml and silicon as constituents of the vapori-zing electrodes or they ,may be placed in the path of the electrical discharge Without being'made a part of the electrical circuit. When boron and silicon are used as electrode material, it is .undesirablefto use the more active hygroscopic rnetais in the same apparatus, as they :react unfavorably withthe :ionic constituents .of the are. In practice, therefore, the hydrogen is rst passed through the apparatus in .the regular marmer to render it .sub-

` stantially free of impurities, and the purified hy drogen is then put through an electric arc Vin which the electrodes are .of boron or silicon according to 'the hydrde which it is desired tofonn. One of the electrodes may be vof mercury ergallium, as these metals are .capable of withstanding the high temperatures which prevail in idle boron! and'silicon arc. Mercury .and gallium, of course, vaporize under the intense heat, but condense again when cooled.

All of the gaseous hydrides formed by my meth 0d and apparatus are stable compounds at leastn their own atmosphere. is proven by the fac-t that mercury switches vusing the hydrides as gas fills are iniinitelymoreenduring than switches using the `uncornbined gases.

It will be'understood that the solids precip- Whena physical of'helum and hydroi itat-.edm lthe apparatus by the hygroscopic metals may be removed by connecting the outlet 29 to a f filter of lany desired construction, preferably.

howevenusinlg cottonas the 'filteringl medium..` What' claim, therefore, ist-' y f f 1, The methodoi preparing ages thai'l is characterized by'its superior arc' suppressing properties, aslcompared with` hydrogen, and'ts relative inability, alsor as comparedwith hydrogen, to react wither be absorbed by'tantalum, said method consistingr in subjecting substantial quantities of y hydrogen and some gas taken from a group conf sisting of helium, neoniand. argon, to the action of an electric arc in the presence of ionized hygro-y scopic fmetals.

2.y The method lof preparing a gas thatis charyso acterized by yitsr superior are suppressing properf f f f ties, as compared Withhydrogen, and its relativey inability, valso as' compared withy hydrogen, kto ref act with or be absorbed by tantalum,'said methodv oonsstingin subjecting substantial quantities of vhydrogen and some gastaken from a' group consistingof helium, yneon and argon tothe action of y f an electric are' inr the present-@iol an ionized hygroscopicr metalv and tiran-lunay ions.

]3. Themethod of preparing a gas that isl chari acterized by its superior are suppressing proper ties, as compared with hydrogen, and its r relativer inability, yalso as compared `with hydrogen, to rreact lwith or ybe absorbed yby tantalum,A said rmethod consisting in subjecting 'a .mixture of' helium and'hydrogen in the approximate jpropor- A'tion oi two volumes of helium. to one `of hydro? Agen to the action of 'aneleotric arc 'in .the lmesence l z f sodium, pot-assiumcalcium, black phosphorous',

of rionized metalsr chosenffrom .a group comprising magnesium, :csiuinC and titanium.' y

#4. The rmetlmd of preparing Va gasr that is lcharacirerizedy by its superior are suppressing s s properties,A vas compared with hydrogen, audits relative inability, also as compared with hydrogen, to react with or be absorbed by tantalurrr said method consisting in subjecting a, mixture of substantial quantities of helium .and hydrogen to the action of an electric arc in which one of the electrodes is composed.V of a. mixture of substantially pure sodium and titanium.

5. The rnethodof chemically uniting helium and hydrogen to'i'ormV a hydride which consists in subjecting a mixture of the two gases to the ac-Y tion of an electric are in the presence of sodium and titanium ions.

6. The method of chemically tmiting vhelium and substantial quantities of hydrogen to form a hydride which consists in subjecting a mixture of the two gases tothe action of an electric are inthe presence of ionized hygro'scopic metals.

'1. jThe method of forming helium hydride which consists 'inpassing amixture of helium and hydrogen through a series of .electric arcs in which strong hygroscopic jmetals are ionic constituents of one arc and calcium or titanium are ionic constituents .ofthesucceeding arc. v 8. '111e 4gaseous product ,formed 'by passing a mixture of hydrogen and helium through an electrie are in the presence of ionized hygroscopie metals, and having a probable ilormula .of Hel-I.

9, Helium hydride instable form.

CARL J. WARNKE 

